OK, this method of checking weather a KV is banned or not is designed for KV Dealers.
or people who are buying KV's in bulk and sharing them, as it does require a Tagged box.

OK, here is what you will need.

- 1x JTAG'd Xenon Xbox

- 1x Unbanned KV

- 1x Nand Reader, you can use LPT, but i would highly recommend a Usb Spi Reader, as LPT takes roughly 1 hour to read/write 16mb Nand, and Usb Spi takes roughly 2 mins

- FLash360.exe

you will need to read your nand and retrieve your CPU & DVD key, do this using a Linux boot loader. (i would recommend xellous) & (Make sure you save your original nand)
once you have your Nand, CPU & DVD Keys, you will need to remove the JTAG wires, but leave the LPT wires on.as shown underneath




once you have taken the JTAG connections off, you will need to write your original nand back to the motherboard. so you have your xbox back to its original state.
but you now have the CPU & DVD Key, which means you are able to use Flash360 to swap KV's.

and you now have your KV tester, so just swap the KV as you normally would when unbanning, then you will need to write it to your xbox via LPT or USB using command prompt

and then sign into xbox live, if it signs in, voila your KV is unbanned, Microsoft will have no way of flagging it because the JTAG connections arn't made;

j2d2.2 to j1f1.4
j2d2.1 to j1f1.3
j2d2.4 to j2d2.7

Hope this helps a few KV Dealers out there. or anyone looking for a method to do this without Flagging the Keyvault

Here is a few useful command lines, assuming your working from the C: drive and using usb;

- Write entire 16Mb nand - C:Nandpro20bnandpro.exe usb: -w16 nand.bin
- Read entire 16Mb nand - C:Nandpro20bnandpro.exe usb: -r16 nand.bin
- Extract KV from Nand - C:Nandpro20bnandpro.exe usb: -r16 kv.bin 1 1
- Write KV to Nand - C:Nandpro20bnandpro.exe usb: -w16 kv.bin 1 1
- Write Xellous to Nand - C:Nandpro20bnandpro.exe usb: -w16 xellous.bin 0 50 (make sure xellous image is in Nandpro folder)